Locking device for chair bases



Get. 28 1924.

R. K. DAWSON LOCKING DEVICE FOR CHAIR BASES Filed Sept. 9, 192a Tram 5K5 Patented Get. 28, 1924.

ROBERT K. DAJ/SON, OF AKRON, NEW YORK.

LOCKING- DEVIOE FOB CHAIR BASES.

Application filed September 9, 1922.

To all 20. mm it may concern:

Be it known that I, Bonner K. DAWSON, a subject of the King of Great Britain, residing at Akron, in the county of Erie and State of New York, have invented a new and useful Improvement in Locking Devices for Chair Bases, of which the following is a specification.

This invention relates to improvements in chair bases of the kind which are adjustable to hold the chair seat at different distances above the chair legs; and more particularly to means for locking the adjustable members against relativemovement, so that the elevation of the chair seat cannot be accidentally or unintentionally changed.

Many different locking devices of this kind have heretofore been devised for this purpose but most of these devices are not positive in their action, others are expensive to manufacture, and still others wear out rapidly due to the fact that they support the weight of the occupant of the chair.

The objects of this invention are to provide a locking device for holding the adjustable members of a chair base against relative movement, which is inexpensive to manufacture and positive in its action; also to provide a lock of this kind which does not support any weight and which is so constructed and arranged on the chair base that the lock is subjected to practically no wear; also to improve the construction of locks of this kind in other respects hereinafter specitied.

In the accompanying drawings:

Fig. 1 is a side elevation, partly in section, of a chair base having a locking device embodying this invention arranged thereon.

Fig. 2 is a fragmentary central sectional elevation thereof.

Figs. 3 and i are sectional plan views thereof on line 33, Fig. 1, showing the locking device in its locked and unlocked positions, respectively.

Fig. 5 is a fragmentary elevation thereof showing the locking device in released posi tion to permit adjustment of the parts of the chair base.

A represents the legs of a chair, the inner ends of which form a central hub portion and are clamped together by any desired or usual means, including a clamping nut B. C represents a seat supporting member which is rigidly secured to the upper end of a spindle or stem D which is preferably Serial No. 587,064.

screw threaded and extends loosely through the hub of the chair legs and the clamping nut B. E represents the usual adjusting nut having a central threaded part which 50 engages the threads of the chair spindle D and which bears on the clamping nut B, the adjusting nut having an outwardly extending web or hand Wheel by means of which the adjusting nut can easily be turned by hand. The adjusting nut E is to the chair spindle D, this spindle may be raised or lowered with reference to the chair legs, whereby the elevation of the chair seat from the floor or other support on which the chair rests may be varied as desire-d. All

of these parts have heretofore been used in connection with chairs and of themselves constitute no part of this invention.

In order to prevent the turning of the chair seat relatively to the base from changing the elevation of the seat, means are generally provided for preventing relative movement between the adjusting nut and the chair spindle. For this purpose I provide a locking device F which, in the particular construction shown, is made of stamped metal and is provided with an enlarged portion f having a hole through which the spindle. D extends and an extension or handle f which projects radially from one side of the enlarged portion 7.

This enlarged portion is provided with a lip or tongue f which extends into the hole through the enlarged portion and is adapted to enter into a keyway or slot d in the spindle to prevent the locking device F from turning relatively to the spindle. Any other means for permitting the locking device to move lengthwise of the spindle and to prevent the same from turning relatively to the spindle may be used.

In order to enable the locking device F to engage the adjusting nut to hold the same against turning relatively to the spindle, the extension of the locking device, in the construction shown, is provided with a downwardly extending lip or portion f which may, if desired,- be formed by punchlng the same out of the extension 7'' of the locking device and which is adapted to engage a part of the adjusting nut to hold the same against turning. Any suitable means may be provided on the adjusting nut to cooperate with the locking lip 7, a plurality of holes 9 being provided through the web of the adjusting nut, inthe construction shown, into which the locking lip may enter, two of the holes being shown. The holes 9 in the web of the adjusting nut and the lock ing lip f are so formed that the locking device F will drop by gravity into a position in which the locking lip will enter into one or another of the holes 9 in the adjusting nut, as shown in Figs. 1, 2 and 3. When the locking device is in this position, the adjusting nut is positively held against turning relatively to the spindle D and consequently if the seat of the chair is turned so that the spindle is rotated relatively to the chair legs, the adjusting nut E will r0- tate with the spindle so that the elevation of the seat will not be changed. llf it is desired to change the elevation of the seat, it is only necessary to raise the extension or handle of the locking device F so as to move the lip or portion 7 out of the hole 9 of the adjusting nut, whereupon the nut may be freely turned in either direction to change the elevation of the seat. if desired, the locking device may be moved into the position shown in Fig. 5 in which it binds on the spindle D, due to the weight of the handle or extension 7, so that the adjusting nut may be freely turned. After the nut has been turned to effect the desired adjustment, the locking device F is released from its engagement with. the spindle so that the outer end thereof will lie upon the adjusting nut, as shown in Fig. 4-. The turning of the seat in either direction with reference to the of the chair will then cause the locking lip or portion f to drop by gravity into one of the holes g of the adjusting nut and securely lock the nut to the spindle. The outer end of the locking device forms a finger piece or grip f by means of which the lock device may be readily moved lengthwise of said spindle to place the locking lip f into or out of engagement with a hole in the adjusting nut, and the weight of this part of the locking device also ensures the engagement of the lip in a hole in the adjusting nut.

The locking device described. is thoroughly reliable in its action since the device will fall by gravity into the locking posi' tion. Furthermore, the engagement of the locking device with the spindle and the adjusting nut positive so that it is impossible to turn the spindle relatively to the adjusting nut without lifting the locking device. The locking device is simple and inexpensive in construction, since it may he made entirely of stamped metal, and the locking device is extremely durable since none of the weight of the occupant of the chair is transmitted to the locking device, the locking device merely lying loosely on the adjusting nut.

I claim as my invention:

In a chair, the combination. of a chair base, a spindle rotatably supported on said base and having a threaded portion, an ad justing nut engaging said threaded portion for varying the elevation of said spindle with reference to said base, and a locking device consisting of a relatively thin metal plate having an enlarged portion provided with an aperture through which said spindle loosely extends, and having a part perma nently engaging with a cooperating part of said spindle to prevent at all times the turn ing of said device relatively to said spindle whereby said device is freely movable lengthwise of said spindle independently of said nut, said locking device having a radial extension forming a handle whereby the device may he readily manipulated, said handle having a downwardly projecting part formed integral therewith and adapted to engage with a recess on said nut when said device rests on said nut to hold said nut against turning relatively to said spindle, said radial extension also serving as a weight which tends to move said downwardly projecting part on said lateral extension into engagement with said recess in said nut, and whereby said device is adapted to grip parts of said spindle when the device is out of engagement with said nut, to permit the adjustment of said nut.

ROBERT K. DAWSON. 

